Explore This Park

Contact Us

#Sciencedeskdigs: Camera

NPS Photo/ M.Reed

There is something about the night sky that excites the human sense of wonder and imagination, making it an important resource for us to protect. Night Skies Research Scientist, Li-Wei Hung helps protect the darkness in our national parks so visitors can experience it for years to come. Read more below to hear about the tools she uses to do this job.

What is it?
This is a charged-couple device (CCD) camera. The camera is essentially a sensor that detects light. It is mounted to a commercial lens and filter wheel with 2 filters— a B (blue) and V (visual) filter. The V filter is used to show what humans can see since the camera can pick up more wavelengths of light than the human eye. The blue filter is used to detect blue photons that are in the sky. We care about measuring blue photons because they are most harmful to our dark adapted night vision.

NPS Photo/M.Reed

This set-up was customized in order to take panoramic images of the sky at night. We take about 45 images and mosaic them together to get a picture of the hemisphere. We use these images to find light domes near cities to assess night sky conditions and amount of light pollution in parks. We have about 525 nights of data from about 120 NPS parks. A small collection of these photos can be seen on our Night Sky Maps and Graphics gallery page. The last park we used this camera was at Scott’s Bluff National Monument in Nebraska.

I used to study planets outside of our solar system and have always been fascinated by space. I am very happy to work for the park service and use a lot of skills I learned while studying astronomy. I feel like my work has an immediate application and impact that helps wildlife, parks, and visitors.